Centrifugal machine



April 30, 1929. I L. n. JONES I CENTRIFUGAL MACHINE Filed April 9, 1926 2 Sheets-Sheet 1 20 0 AQ nvjntoz 33 alien 10130 E g E Hllllllll April 30, 1929. D s 1,711,468

CENTRIFUGAL MACHINE Filed April 9, 1926 2 Sheets-Sheet 2 min? IN VEN TOR. 9W A TTORN YS.

Patented Apr. 30, 1929.

UNITED STATES PATENT OFFICE.

LEO D. JONES, or PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO THE sHARPLEs. sPEoIA'L'rY COMPANY, OF PHILADELPHIA, PENNSYLVANIA, A CORPORATION OF DELAWARE.

CENTRIFUGAL MACHINE.

Application filed April 9, 1926. Serial No. 100,796.

This invention relates to centrifugalmachines and more especially to machines for concentrating the dispersed phase of an emulsion or suspension and separating the concentrated emulsion from the pure continuous phase.

In devices of this character the emulsion or suspension is fed into a centrifugal bowl and as it passes along the bowl the dispersed phase is gradually concentrated by centrifugal action either near the axis or the periphery of the bowl, depending upon the character of the emulsion or suspension. The concentrated emulsion and the pure continuous phase are discharged from the bowl through passageways leading from the bowl at different radial distances from its axis. Each discharge is controlled by a weir which may constitute a portion of the surface of the passageway or may comprise a separate member associated with the discharge passageway. The concentration of the emulsion depends upon the ratio of the rate of discharge of the concentrated emulsion to the rate of discharge of the continuous phase. Machines of this type now in use have the disadvantage that any decrease in capacity below the normal capacity of the machine results in a decrease in the ratio of the rate of discharge of the concentrated emulsion to the rate of discharge of the continuousphase thereby increasing the concentration of the emulsion. If the capacity at which the machine .is operating is sufficientliy reduced the emulsion may become sufiiciently concentrated to produce coalescence or cloggage of the discharge. Moreover, this type of machine has the additional disadvantage that any wriation in thespeed of rotation of the bowl produces a variation in the percentage concentration of the emulsion.

the continuous phase discharge by weirs so.

designedthat the ratio of the rate of discharge of concentrated emulsion to the rate of discharge of the pure continuous phase is sub- An object ofthis invent-ion is a centrifugal tained uniform by forming the weirs so that their edges lie along arcs of equal diameter circles having their centers coincident with the axis of the bowl. The ratio bctweenthe rates of discharges may be determined by the width of the weirs. WVith such an arrangement, the thickness of the discharge crests is substantially the same for both weirs at any given capacity or speed of the machine, and the volumes of the discharges bear the same relation to each other as do the width of the weirs controlling them. The widths of the weirs are so chosen that the desired concentration of the emulsion is. obtained, and if it is desired to vary the concentration of the enulsion, the ratio of the weir widths is chan ed. i

This invention is of particular uti1ity-in cream separators. WVith machines of the type heretofore on the market, it is necessary to operate each machine at a definite and predetermined capacity and speed in order to obtain a certain percentage of butter .fat in the cream. A decrease in capacity results in an increase in the percentage of butter fat in the cream, and if the capacity is decreased sufficiently, cream ceases to flow entirely. Also a variation in the speed of operation of the machine results in a variation in the percentage of butter fat in the cream. A cream separator embodying this. invention, however, discharges cream having .a uniform percentage of butter fat, at difierent capacities and speeds of the machine.

Other objects, novel features and advantages of this invention will be apparent from the following specification and accompanying drawings, wherein Figure 1 illustrates in vertical section partially broken away a centrifugal machine bowl designed to discharge concentrated emulsion of uniform ties;

Figs. 2 and,3 are plan views of theweirs for controlling the discharges;

Fig. 4 illustrates diagrammatically the principle of the invention;

Fig. -5 is a vertical section partly away invention;

broken of a cream. separator embodying the percentage at all capaci- Fig. 6 is a similar enlarged View of the head of the bowl of the separator shown in Fig.

Fig. 7 is a section on the line 7-7 of Fig. 6;

Fig. 8 is an enlarged sectional fragmentary view of a modified head; and

Fig. 9 is a section on the line 9-9 of Fig. 8.

Referring now to Figs. 1 to 3 inclusive, 10 designates a centrifugal machine-bowl having a head 11 which may be suitably connected to a spindle. The lower portion of the bowl is provided with a tubular projection 12 through which an emulsion or suspension may be introduced from a nozzle 12 and which may fit into a suitable guide bushing. In the head 11 are provided two outlet passageways 13 and 14 of which 13 leads from a a point nearer the axis of the bowl than does 14 and terminates at a point below the termination of 14. An annular disk 15 is screwed into the lower face of the head 11 and surrounds one end of the outlet 13. Between the disk 15 and the inner surface of the bowl is arranged a plurality of wings 15, three being preferred, to cause the liquid in the annular space between the disk and the bowl to rotate at the same speed as the bowl. One or more portions of the disk are cut away to provide one or more weirs 16, the edge or edges of which lie on the circumference of a circle concentric with the axis of the head. The passageway 14 leads into an annular channel 17 which is substantially covered by an annular collar 18. One or more portions of the collar 18 are cut away to provide one or more weirs 19, the edge or edges of which lie on the circumference of a circle concentric with the axis of the head and of the same diameter as the circle on the circumference of which lie the edges of the weir or weirs 16. The depth of the crests over the weirs 16 and 19 depends on the distance of the surface of the liquid in the bowl from the axis ofthe bowl and. as the edges of the weirs 16 and 19 are equally distant from the axis of the bowl, the depth of both crests will be substantially the same at any given capacity or speed of the machine. The ratio of thedischarges is therefore dependent upon the ratio of the width of the weirs 16 and 19. v

Although in Fig. 1 means are not disclosed for rotating the bowl 10 and receiving the discharges from the outlets 13and 14, it is to be understood that it is contemplated to mount the bowl 10 in a machine substantially similar to that shown in Fig. 5 in which means are provided for rotating the bowl, and feeding liquid into the bottomof the bowl and discharge compartments are provided for receiving the liquid dischargedthrough the outlets 13 and 14. V

Assume that the bowl 10 is being rotated into the lower portion thereof. As the emul- 10. and an emulsion or suspension is being fed I trated either near the axis or the periphery of the bowl depending upon the character of the emulsion or suspension. Assuming that the concentrated emulsion is lighter than the continuous phase, the concentrated emulsion will pass over the weir or w'eirs16 and discharge through the passageway 13 and the pure continuous phase will pass between the edge of the disk 15 and the inner face of the bowl 10 through the passageway 14 and thence to the annular channel 17 from whence it discharges over the weir or weirs 19. The ratio of the discharges through these passageways is de-' pendent upon the relative widths of the weirs and will remain constant at different capacities and speeds. The widths of the weirs 16 and 19 are so chosen that the desired concentration of emulsion is obtained. In the drawings the weir 16 is disclosed as being narrower'than the weir 19 but might be of the same or greater width depending upon the character of the emulsion or suspension being treated. When it is desired to change the concentration of the emulsion another collar 18 having weirs of different widths may be substituted or a different disk 15 having weirs of different widths may be utilized. Preferably a change of concentration is obtained by replacing the collar 18 as the collar is more accessible than the disk 15.

Reference to Fig. 4 will make clear the principle of the invention. The tank 10 corresponds to the bowl 10 into which the suspension is introduced through the pipe 12. Liquid may escape over a weir 16 or through a passageway 14 and over a weir sage 14 of the centrifugal machine; The analogy of the operation of the machine disclosed in Figs. 1 to 3 is as follows. Assume that an emulsion or suspension is supplied to the tank 10 throughthe pipe 12 and that the emulsion concentrates on the upper surface. The concentrated emulsion flows over the weir 16 and the pure continuous phase flows through the channel 14 and over the weir19. The level of the discharge crests over the weirs 16 and 19 is substantially the same. Since the weirs are of equal height the ratio of the discharges over the weirs is therefore dependent upon the ratio of their widths. With any given ratio of the widths of the weirs the emulsion discharged over the weir 16 will be of a definite concentration irrespective of the level of the liquid in the tank I If it is desired to vary this concentration, the width of the weir 19 may be varied and when varied'the concentration of the emulsion discharged over the weir 16 will rcsageway 14 corresponds to the discharge pasvariations in the speed of rotation of the bowl and in the rate at which the substance to be treated is supplied thereto.

Referring now to Figs. 5, 6 and 7, reference numeral 20 designates a standard support ing a casing 21, and being provided with a bracket 22 overhanging the casing. A bearing 23 is supported by the bracket 22, and has mounted therein a spindle 24 passing through a sleeve 25 and which may be driven by any suitable means such, for example, as a Worm 26 and worm wheel 27. A centrifugal vessel or bowl 28 is supportingly coupled to the spindle 24 through the medium of a member which also constitutes the head 29 of the bowl 28. In the head 29 is provided a plurality of skim milk discharge channels 30 leading from the bowl 28 at points near its periphery to an annular groove or port 31 which is partially closed by an annular member 32, which'constitutes a weir for the skim milk discharge. A cream discharge duct is provided in the member 29 and consists of a slot 33, the bottom of which extends parallel to the axis of the bowl 28 and is spaced therefrom a distance equal to the radial distance of the inner edge of the annular weir 32. A cup-shaped member 34 is carried by the head 29 and projects into the bowl 28, it being so arranged as to provide a narrow annular passageway between the periphery of the end prO ecting into the bowl and the interior of the bowl 30, said passageway affording communication between the interior of the bowl and the channels 30.

The lower end of the bowl 28 is steadied by means of an arrangement 36 commonly known as a drag assembly. Thewhole milk to be separated is conducted through a suit able pipe 37 from a source of supply not shown and is introduced into the bowl through a nozzle 37 Cover compartments 38and 39 are provided around the top of the bowl 28 in position to receive milk and cream discharged through the ducts 30 and 33.

According to this arrangement, the skim milk discharge is controlled by a weir, the edge of which lies on the circumference of a circle, the center of which is coincident with the axis of the bowl. The cream discharge is likewise controlled by a weir, the edge of .which,for all practical purposes, lies on the circumference of a circle the center of which is coincident with the axis of the bowl and which is of the same radius as the circle on the circumference of which the edge of the skim milk weir lies. WVith this arrangement the ratio of the cream discharge to the skim milk discharge is uniform at different capacities and speeds of the device. The thickness of the discharge crests is dependent upon the radial distance of the surface of the liquid from the axis 9f the bowl and as the weirs are at equal radial distance from the axis, the thickness of-the crest over each is substantially the same. The ratio of the cream discharge to the skim milk discharge depends thereforeupon the ratio of the width of the weirs. A change in the radial distance of the surface of the liquid from the axis of the bowl either because of a change in caturn is dependent upon the ratio of the widths of the weirs controlling the discharges. The effective width of the cream slot or weir is variable by means of a screw 40 which is movable into and out of the duct in a transverse direction. As is clearly shown in Fig. 7, longitudinal movement of the screw 40 varies the width of the slot 33. This same effect is also obtainable in the modification dis-closed in Figs. 8 and 9. Here a screw 41 is provided in the bottom of the slot and its inner end is cut away so that, in the position shown in Fig. 9, the portion 41 of the screw lies wholly Within a socket at the side of the cream slot. Rotation of the screw, however, brings the edge of the portion 41 into the cream slot, thereby "arying the effective width of the slot. By means of either type of screw, the ratio between the width of the cream discharge weir and the skim milk discharge weir may be varied. As the edges-of the weirs controlling these discharges are equally distant from the axis of the bowl, variation in the width of the cream discharge weir effects a variation in the ratio of the cream discharge to the skim milk discharge. A variation in the level of the whole milk in the bowl 30 produces a proportionate variation in both the cream and skim milk discharges, but does not affect the ratio of the cream discharge to the skim milk discharge.

Although the annular member 32 has been disclosed as having its ent-ireinner edge constituting a weir for controlling the skim milk discharge it is evident that there may be substituted a Wider annular member provided with one or more cut-away portions having their edges at the same distance from the axis as the bottom of the cream slot, thereby providing one or more weirs for controlling the skim milk discharge. Variation in the ratio the weir controlling the cream slot should be of the same curvature as that of the annular dam for the skim milk. discharge. Very satisfactory results are obtainable, however, with a cream slot of rectangular cross-section. The cream discharge is but a small fraction of the skim milk discharge and consequently the cream slot is very narrow. Thus, the cream discharge weir need not be curved but Wlll give very satisfactory results although straight. It is, of course, within the spirit of the invention to make the cream weir of the same curvature as that of the skim milk weir, if absolute uniformity is desired. For all practical purposes, it is not necessary to have the weirs of equal curvature,

It is, of course, understood that various structural modifications may be made without departing in any way from the spirit of the invention as set forth in the appended claims.

In this connection it is pointed out that an important feature is that the weirs over which the constituents into which the substance fed to the bowl is centrifugally separated, must be located at such relative distance from the axis of the bowl that some of each constituent will be discharging over its weir at substantially all rates of feed ofthe substance to the bowl. When cream is being separated from milk, a cream weir located radially inward 7 0f the milk weir would necessitate the build- 6 lighter substance may, without undesirableing up of a layer of cream above the surface of the skim milk that is discharging-over its weir. This would cause thecream globules to coalesce into continuous butter fat unless milk is supplied to the bowl at such a rate that'the crest over the milk weir is at least as near the axis of the rotor as the cream weir.

But, if the cream and milk weirs are at the ous butter fat; and therefore in the separation same distance from the axis of the bowl there is a concentrating of the emulsion, and milk and cream will both discharge over their respective weirs regardless of the rate at which milk is fed to the bowl, the proportion of cream and skim milk being determined by the relative widths of the weirs. In separating substances ofmuch pharacter that the alteration of it, be discharged over a weir that is radially inward of the other weir, the weirs may be placed at different distances from the axis of the bowl and the relative depths of the crests over the two weirs may be maintained uniform, -'n accordance with the principles of this invention, at different rates of feeding and different speeds of rotation so long as the relative distance of the .weirs from the axis is such that, having due regard for the relative specific gravities of the separated constituents, some of each constituent will be discharging over its weir at substantially all rates of feed to the bowl. In the practice of this-invention the weirs employed are not to be confused with mere orifices of which the dimensions may be varied. Such orifices act merely as valves and the volume of flow through them varies greatly with variations in speed of rotation and their position with respect to the surface of the liquid within the bowl.

References in the claims to the maintaining of various conditions at any or all capacities or rates of feed or speeds of rotation, or irrespective of speed or capacity, are, of course, intended to refer only to operative conditions, i. e., conditions under which the desired separation will occur. In general, such conditions are that the speed of rotation will be great enough to keep the liquid in place in the bowl substantially in the form of a hollow cylinder, and to effect the desired separation; and that the capacity or rate of supply to the bowl will be low enough to avoid causing discharge from the supply opening as well as from the discharge openings and to avoid clogging of dischargeopenings and to ensure that the substance will be in the bowl long enough to be separated. Thus, in the practice of my invention emulsions may be concentrated and mixtures may be divided into predetermined fractionsby having weirs that are of properly selected circumferential length and are located either at the same distance or at different distances from the axis of the centrifugal bowl. In'all instances the lengths of the weirs will be such as to maintain substantially' uniform the relative depths of the crests over them in spite of variations in the rate of supply of material to the bowl and the rate of rotation of the bowl. When cream is being separated from full milk any arrangement of of milk and of other substances of such character'that a product separated therefrom by centrifugal force is undesirably altered when. a layer f that product is subjected to centrifugal force, the discharge of some of each product over its weir at all speeds and all rates of supply is at equal distances from the axis of the bowl. But, when the substance that is being separated is of such character that the separated. products thereof may be formed into layers or strata in the bowl without undesirable change, such as undesirable coalescence of dispersed particles, then there is a liquid balance of products within the bowl on opposite sides of the disk 15 and the weirs maybe at different distances from the axis of the'rotor Letters Patent is:

,1. A machine for concentrating emulsion comprising a centrifugal bowl, means for sepbest attained by having the weirs arately discharging concentrated emulsion and pure continuous phase and means for maintaining constantthe ratioof said discharges at any speed or capacity of the machine.

2. A machine for concentrating emulsions comprising a centrifugal bowl, means for discharging concentrated emulsion and pure continuous phase from said bowl from points at different radial distances from the axis of the bowl and means for maintaining constant the ratio of the discharges irrespective of the capacity and speed of the machine.

3. A machine for concentrating emulsions comprising a centrifugal bowl having discharge passageways leading from points at different radial distancesfroin the axis of the bowl and weirs controlling the discharge from said passageways, said weirs having their edges equally distant from the axis of the bowl. o

4. A machine for concentrating emulsions comprising a centrifugal bowl having discharge passageways leading from points at different radial distances from the axis of the bowl and weirs of different widths controlling the discharge from said passageways, said i V weirs having their edges equally distant from the axis of the bowl. 5. A machine for concentrating emulsion comprising a centrifugal bowl having discharge passageways leading from points at different radial distances from the axis of the bowl and weirs of variable widths controlling the discharges from said passageways; said weirs having their edges equally distant from the axis of the bowl.

' 6. A machine for concentrating emulsions comprising a centrifugal bowl having discharge passageways leading from po nts at different radial distances from the axis of the bowl and weirs controlling the discharges from said passageways, one of sand weirs being of variable width and all the weirs having their edges equally distant from the axis of the bowl.

7. A machine for concentrating emulsions comprising a centrifugal bowl having passageways leading from points at different radial distances from the axis of the'bowl, annular members controlling the flow through each of said passageways, each of said annular members having a portion cut away to provide arcuate weirs of equal curvature, the centers of which are coincident with the axis of the bowl.

8. A machine for concentrating emulsions comprising a centrifugal bowl having discharge passageways leading from points at difierent radial distances from the axis of the bowl and an annular member surrounding one end of each discharge passageway,each of said annular members having a portion cutaway 1 to provide arcuate weirs of equal curvature,

sageways, said annular member and disk having portions cut away to provide -arcuate weirs of equal curvature, the centers of which are coincident with the axis of the bowl.

10. A machine for concentrating emulsions comprising a centrifugal bowl having a passageway leading from a point near the axis of the bowl and a passageway leading from a point near the periphery of the bowl, an annu-- lar channel communicating with the outer end of the passageway leading from a point near the periphery of the bowl, an annular member substantially closing said channel, and an annular disk projecting into the bowl and enclosing the inner end of the passageway leading-from ,a point near the axis of the bowl, said annular members being cut away to provide arcuate weirs of equal curvature whose centers are coincident with the axis of the bowl.

11. A machine for concentrating emulsions comprising a bowl having passageways leading from points at different radial distances from the axis of the bowl, an annular member controlling the flow from one of said passageways and an annular member controlling the flow to the other passageway, said annular members having portions cut away to form arcuate weirs of equal curvature whose centers are coincident with the axis of the bowl, said annular members being removably connected whereby the relative circumferen tial extent of said weirs may be varied.

'12. In a device of the character described a centrifugal bowl having discharge passageways leading from points at different radial distances from the axis of the bowl, weirs controlling the discharge from said passageways,'the edges of said weirs being equally distant from the axis of the bowl and means for varying thewidth of one of said weirs. 13. In a device of the character described, a centrifugal bowl having discharge passageways leading from points at difierent radial distances from the axis of the bowl, weirs controlling the discharge from said passageways and means for maintaining uniform the ratio of the discharges through said passageways at all capacities of the machine.

14. In a cream separator, a rotatable bowl having cream and skim milk discharge outlets controlled by weirs equally distant from the axis of the bowl and means for varying lie 1,6. In a cream separator, a rotatable bowl having cream and skim milk outlets controlled by weirs equally distant from the axis of the bowl and a screw having aportion adapted to move into and out of said cream outlet to vary the effective width of the weir controlling said cream outlet.

17. In a cream separator, a rotatable bowl having cream and skim milk outlets controlled by weirs equally distant from the axis, of the bowl and a screw arranged to traverse the cream outlet whereby the effective width of the weir controlling said cream out let may be varied.

18. In a cream separator, a rotatable bowl having a skim milk outlet and a cream slot at equal distances from the bowl axis, and means to vary the effective width of said cream slot in a circumferential direction.

19. In a cream separator, a rotatable bowl having a skim milk outlet and a cream slot at equal distances from the bowl axis, and means to vary the cross sectional area of said cream slot while maintaining an edge of said cream slot at a fixed distance from the axis of the bowl.

20'. In a cream separator, a rotatable bowl having skim milk and cream outlets at different radial distances from the axis thereof, weirs controlling said outlets and located at substantially equal distances from the bowl axis a cylindrical member projecting into the bowl between said cream and skim milk outlets and means for varying the eflective width of one of said weirs.

21. In a cream separator, a rotatable bowl having skim milk and cream outlets at diiferent radial distances from the axis thereof, weirs controlling said outlets and located at substantially equal distances from the bowl axis, a cylindrical member projecting into the bowl between said cream and skim milk outlets and means for varying the effective width of the weir controlling said cream out let.

22. In a cream separator, a rotatable bowl having a cream slot and a skim milk outlet terminating in an annular channel, an.annular member overlying said annular channel to constitute a weir for controlling the discharge through said skim milk outlet and located at substantiall the same distance from the bowl axis as t e edge of said cream slot and means for varying the effective width of said cream slot in a circumferential direction. y

23. In a cream separator, a rotatable howl having a cream slot and a skim milk outlet terminating in an annular channel, an annular member overlying said annular channed to constitute a weir for controlling the discharge through said skim milk outlet, the bottom of said cream slot and the inner edge of said annular member being at the same radial distance from the axis of the bowl and means for varying the width of said cream slot.

24. In a; centrifugal machine, a bowl having outlets at different radial distances from the axis of the bowl and means for maintaining constant the ratio of the discharge through said outlets irrespective of the distance of the surface of the liquid in the bowl from the axis of the bowl.

25. A device of the character described ently of the proportion in which the products discharged exist in the substance introduced into the bowl.

27. In a centrifugal machine, a centrifugal bowl, and means for separatel discharging therefrom products of centri ugal treatment in substantially constant ratio at varying speeds of rotation of the bowl.

28. In a centrifugal machine, a centrifugal bowl having discharge passageways leading from points within the bowl that are at different radial distances from the axis ofthe bowl, weirs controlling the discharge from said passageways and located at such relative distance from the .axis of the bowl that some of each constituent of the substance fed to the bowl will discharge over its weir at substantiall all rates of feed of the substance to the owl, and means for varying the circumferential extent of one of said welrs.

29. In a device of the character described, a centrifugalbowl having discharge passageways leading from points at different radial distances from the axis of the bowl, weirs controlling the discharge from said passageways and means for varying the volume of the discharge through one passageway without varying the crest of the liquid discharging over the weir thereof.

30. In a centrifugal machine, a centrifual bowl having discharge passageways leading from points within the bowl that are at different radial distances from the axis of the bowl, and Weirs. controlling the discharge from said passageways and being located at such relative distances from the axis of me bowl that some of each constituent of the substance fed to the bowl will discharge over its eir at substantially all rates of feed of the substance to the bowl and said Weirs having relative circumferential lengths such that the radial depth of liquid flowing 'overone of said Weirs is equal to the radialdepth of 10 In testimony whereof, I haye signed my 15 name to this specification.

LEO D. JONES. 

